package com.zy.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.zy.dto.Result;
import com.zy.entity.VoucherOrder;
import com.zy.mapper.VoucherOrderMapper;
import com.zy.service.ISeckillVoucherService;
import com.zy.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.zy.utils.RedisWorker;
import com.zy.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 张宇
 * @since 2024-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    private ISeckillVoucherService seckillVoucherService;

    @Autowired
    private RedisWorker redisWorker;

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    @Autowired
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //在类初始化之后执行，因为当这个类初始化好了之后，随时都是有可能要执行的
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    // 用于线程池处理的任务
    // 当初始化完毕后，就会去从对列中去拿信息
    private class VoucherOrderHandler implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create("stream.orders", ReadOffset.lastConsumed())
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    //处理异常消息
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS s1 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create("stream.orders", ReadOffset.from("0"))
                    );
                    // 2.判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        // 如果为null，说明没有异常消息，结束循环
                        break;
                    }
                    // 解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    // 3.创建订单
                    createVoucherOrder(voucherOrder);
                    // 4.确认消息 XACK
                    stringRedisTemplate.opsForStream().acknowledge("s1", "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pendding订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        }
    }


    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        // 1.多线程,不能从UserHolder里取这个用户id啦
        Long userId = voucherOrder.getUserId();
        // 2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 3.获取锁, 已经在redis里面做判断啦, 不需要再判断了,但是加锁给一个兜底机制
        //boolean isLock = simpleRedisLock.tryLock(1200L);
        boolean isLock = lock.tryLock();
        if (!isLock) {
            // 获取锁失败,返回错误信息
            log.error("不允许重复下单");
            return;
        }
        // 动态代理 作为一个子线程是无法从threadlocal里面取这个proxy
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            lock.unlock();
        }
    }

    /**
     * 秒杀优惠券
     *
     * @param voucherId
     * @return
     */
 /*   @Override
    public Result seckillVoucher(Long voucherId) {
        // 1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.query().eq("voucher_id", voucherId).one();
        // 2.判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始");
        }
        // 3.判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经结束");
        }
        // 4.判断库存是否充足
        if (voucher.getStock() <= 0){
            return Result.fail("库存不足");
        }
        Long userId = UserHolder.getUser().getId();
        //synchronized (userId.toString().intern()) {
        //创建锁对象
        //SimpleRedisLock simpleRedisLock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 获取锁
        //boolean isLock = simpleRedisLock.tryLock(1200L);
        boolean isLock = lock.tryLock();
        if (!isLock) {
            // 获取锁失败,返回错误信息
            return Result.fail("不允许重复下单");
        }
            // 动态代理
        try {
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            Result voucherOrder = proxy.createVoucherOrder(voucherId);
            return voucherOrder;
        } finally {
            lock.unlock();
        }
        //}

    }*/

    /**
     * 秒杀优惠券优化版
     *
     * @param voucherId
     * @return
     */
    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        long orderId = redisWorker.nextId("order");
        // 1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );
        int r = result.intValue();
        // 2.判断结果是否为0
        if (r != 0) {
            // 2.1.不为0 ，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        // 3.返回订单id
        return Result.ok(orderId);
    }

    @Transactional
    @Override
    //不用Synchronized方法(锁是这个实现类的对象),用关键字 synchronized,   事务提交之后才去释放锁,锁定范围得变
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 5.一人一单
        Long userId = voucherOrder.getUserId();
        // TODO 同一个用户加一把锁,不同的用户加不同的锁,每掉一次toString()方法,也是全新的字符串对象,用intern只要值一样,地址就一样
        //synchronized(userId.toString().intern()) {
        // 5.1判断是否已经购买过
        if (query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count() > 0) {
            log.error("您已经购买过该优惠券");
        }
        // 6.扣减库存
        boolean success = seckillVoucherService.update().setSql("stock = stock - 1").eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0).update();
        if (!success) {
            log.error("库存不足");

        }
        save(voucherOrder);


    }
}
